The invention relates generally to transducers, and more specifically to a transducer assembly.
Transducers, such as acoustic transducers, have found application in medical imaging where an acoustic probe is held against a patient and the probe transmits and receives ultrasound waves, which in turn may facilitate the imaging of the internal tissues of the patient. For example, transducers may be employed to image the heart of the patient.
Transducer assemblies generally include a transducer array, such as a two-dimensional transducer array, having one or more transducer elements arranged in a spaced relationship. Additionally, connecting elements are disposed directly underneath a respective transducer element. Spacing between each of the connecting elements is determined by spacing between the respective transducer elements.
The transducer assembly may also include an interconnect structure having a plurality of layers of interconnect configured to facilitate electrically coupling the connecting elements to an external device, such as a cable assembly or readout electronics. Typically, the interconnect structure is formed by stacking a plurality of interconnect layers, where each of the plurality of interconnect layers includes a plurality of conductive traces patterned thereon. The conductive traces may be configured to facilitate coupling connecting elements associated with each of the one or more transducer elements on the transducer array to associated electronics. Furthermore, spacing between each of the plurality of traces in a first direction is configured to match spacing between the connecting elements. Similarly, a spacing between each of the plurality of interconnect layers is configured to match a spacing between the transducer elements in a second direction. Consequently, a desired number of interconnect layers is dependent on the number of connecting elements in the second direction thereby resulting in use of a substantially high number of interconnect layers. A typical transducer may necessitate use of a number of interconnect layers in a range from about 40 to about 100. This increase in the number of interconnect layers results in enhanced complexity of interconnections and is not cost-effective.
Previously conceived solutions have incorporated multi-layer flexible interconnect circuits to facilitate coupling the plurality of transducer elements to an external device, such as readout electronics or a cable assembly. However, these multi-layer flex circuits route conductors on multiple flexible layers parallel to the plane of the transducer elements. Unfortunately, these interconnect circuits are expensive and fail to efficiently utilize space within a catheter. Additionally, acoustic performance of transducers fabricated with such methods has suffered due to the presence of an acoustically unfavorable interconnect circuit immediately underneath the transducer elements.
There is therefore a need for a transducer assembly with reduced complexity of interconnections. In particular there is a significant need for a design of a transducer assembly that advantageously reduces the number of interconnect layers in the transducer assembly. Also, it would be desirable to develop a simple and cost-effective method of fabricating a transducer assembly with reduced complexity of interconnections.